Tuesday, November 10, 2015

Winter Death of PearlMS

PearlMS, tagged by Dr. Jennifer Coulson in 2011 near the East Pearl River in Mississippi, spent most of the 2015 North American breeding season in his previous nesting neighborhood along the West Hobolochitto River near Picaynue, Mississippi. It is not always easy to determine whether a male is nesting, though on several occasions, data showed PearlMS roosting during the day in one particular location – a behavioral pattern that suggests incubation shifts.  Jennifer and her husband, Tom, searched the daytime roost locations, wading through the dark water and mud typical of this lowland forest habitat. They did not find a nest, “only lots of mosquitoes,” and concluded that 2015 was not a breeding year for PearlMS.

Southbound migration and last known location of PearlMS

PearlMS left his summer range on 12 August 2015, taking the western circum-Gulf route as opposed to the trans-Gulf route. At the end of the first day, he overnighted at a roost along the Atchafalaya River, then continued overland through Texas and Mexico, keeping within eyesight of the coast except when crossing the Texas/Mexico border, where he flew 80 miles inland around Reynosa.  On 22 August he passed near the famous River of Raptors migration station near Veracruz, Mexico, but was probably a little too far west to be among the counted!  He followed the contours of Central America and in mid-September reached the lush Pacific forests of the western Colombian Andes. PearlMS moved southwest along the range and slowed some, gaining energy required to traverse the high mountain peaks. Having crossed safely, he spent a few days along the Caqueta River in Colombia, then continued through northeastern Peru into the state of Amazonas, Brazil.  Here, where forested rivers provide ample food for migrating kites, PearlMS slowed again to take advantage of the abundant prey.  


On 13 October 2015, only days from reaching his wintering grounds in southern Rondônia, Brazil, PearlMS’s transmitter went quiet. Unfortunately, the most likely explanation is that he is dead. Dr. Coulson has engaged the help of local scientists, hoping they can access the location of the bird’s last signal to look for any evidence. His last transmission came from a remote area of mixed forest and pasture within a very large farm near a dam, the Saldanha Small Hydroelectric Project on the Saldanha River in the municipality of Alta Floresta D’Oeste in Rondônia, Brazil. Although the biologists have not yet gained access to the area, they intend to persist, hopeful they may find some useful clues.

Tuesday, November 3, 2015

Settling into an Austral Summer

Yesterday's tracking data shows that almost all nine satellite-tagged Swallow-tailed Kites are settled into their South American summer ranges.
Locations of nine satellite-tagged Swallow-tailed Kites.

All but one bird is in southwestern Brazil; Gulf Hammock has returned to Santa Cruz, Bolivia, for the 4th year in a row.

Three kites, Day, Strong River, and Bullfrog, are in the State of Mato Grosso, Brazil, within 100 miles of the Bolivian border.

The four kites in Mato Grosso do Sul, include three return visitors: Palmetto (4th year), Pace and MIA (3rd year), plus newly-tagged, Lacombe. Lacombe is the southernmost kite, nearing the Parana border.

Sadly, we report that PearlMS has not made it to his wintering grounds this year. His signal was lost on 13 October while passing through the state of Rondonia. There are several reasons why we might stop receiving transmissions from a bird we are tracking: a dead storage battery, premature transmitter failure, harness failure, a broken antenna, or mortality. The batteries in these solar-powered transmitters last over five years, and we have never recovered a Swallow-tailed Kite’s transmitter with evidence of harness failure or a damaged antenna. Complete transmitter failure has been extremely rare for these sophisticated devices and we have not confirmed one such case in the last 15 years. 

With the guidance of Dr. Jennifer Coulson, a small group of local scientists has tried to reach the last known location of PearlMS, but they have not had luck accessing this remote area of mixed forest and pasture within a large farm near a hydroelectric dam. PearlMS has transmitted since 2011 and in that time has sent us well over 50,000 miles of tracking data. We will share more of the story of PearlMS in our next blog so please stay tuned. 

Every marked bird of every species we have tracked has provided remarkable insights vital to conservation. We remember this each time we accept the privilege of attaching a transmitter to a bird. Sharing their stories with you is one way we can thank them for their contributions. We thank you for following, and for caring about these incredible birds.